Bioleaching of Pyrite by Iron-Oxidizing Acidophiles under the Influence of Reactive Oxygen Species

After 24h of exposure to acidic media, pyrite generates reactive oxygen species (ROS). Freshly-crushed pyrite with grain sizes between 50-100 μm at a 5 % (w/v), pulp density generated 0.17 ± 0.01 mM H2O2, while 10% pyrite generated 0.29 ± 0.01 mM and 30 % pyrite generated approximately 0.83 ± 0.06 mM. These levels of H2O2 inhibit iron oxidation in iron-grown cells of AcidithiobacillusferrooxidansT but not in pyrite-grown cells. ROS originating from pyrite, which was incubated for 24 h in acidic medium, prohibited pyrite dissolution by iron-grown cells, while pyrite-grown cells were adapted to these concentrations of ROS. Periodical addition of 100 μM H2O2 to pyrite cultures inoculated with pyrite-grown cells did not lower iron dissolution as it was observed with iron-grown cells. By high throughput proteomics analysis, an increased expression of proteins related to oxidative stress management, iron-and sulfur oxidation systems, carbon fixation and biofilm formation was observed in biofilm cells grown on pyrite compared to iron-grown cells.

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Novel Biogenic Silver Nanoparticle-Induced Reactive Oxygen Species Inhibit the Biofilm Formation and Virulence Activities of Methicillin-Resistant Staphylococcus aureus (MRSA) Strain

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2020.00433 ◽

2020 ◽

Vol 8 ◽

Cited By ~ 7

Author(s):

Reham Samir Hamida ◽

Mohamed Abdelaal Ali ◽

Doaa A. Goda ◽

Mahmoud Ibrahim Khalil ◽

Mayasar Ibrahim Al-Zaban

Keyword(s):

Reactive Oxygen Species ◽

Staphylococcus Aureus ◽

Silver Nanoparticle ◽

Biofilm Formation ◽

Methicillin Resistant Staphylococcus Aureus ◽

Reactive Oxygen ◽

Oxygen Species ◽

Methicillin Resistant

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In Vitro Inhibition of Streptococcus mutans Biofilm Formation on Hydroxyapatite by Subinhibitory Concentrations of Anthraquinones

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00999-06 ◽

2007 ◽

Vol 51 (4) ◽

pp. 1541-1544 ◽

Cited By ~ 34

Author(s):

Tom Coenye ◽

Kris Honraet ◽

Petra Rigole ◽

Pol Nadal Jimenez ◽

Hans J. Nelis

Keyword(s):

Reactive Oxygen Species ◽

Streptococcus Mutans ◽

Biofilm Formation ◽

Reactive Oxygen ◽

Oxygen Species ◽

Membrane Perturbation ◽

In Vitro Inhibition ◽

Subinhibitory Concentrations

ABSTRACT We report that certain anthraquinones (AQs) reduce Streptococcus mutans biofilm formation on hydroxyapatite at concentrations below the MIC. Although AQs are known to generate reactive oxygen species, the latter do not underlie the observed effect. Our results suggest that AQs inhibit S. mutans biofilm formation by causing membrane perturbation.

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Reactive Oxygen Species Influence Biofilm Formation of Acidophilic Mineral-Oxidizing Bacteria on Pyrite

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1130.118 ◽

2015 ◽

Vol 1130 ◽

pp. 118-122 ◽

Cited By ~ 1

Author(s):

Sören Bellenberg ◽

Dieu Huynh ◽

Laura Castro ◽

Maria Boretska ◽

Wolfgang Sand ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Hydroxyl Radicals ◽

Biofilm Formation ◽

Laser Scanning ◽

Reactive Oxygen ◽

Laser Scanning Microscopy ◽

Metal Sulfides ◽

Confocal Laser ◽

Water Molecules ◽

Oxygen Species

Reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), superoxide (O2-) and hydroxyl radicals (OH.) are known to be formed on the surface of metal sulfides in aqueous solution under oxic and anoxic conditions. Consequently bacteria which have not been adapted to their presence are metabolically inhibited [1], presumably due to the presence of these ROS. Pyrite-grown cells ofAcidithiobacillus ferrooxidansT, in contrast to iron (II)-grown cells, were able to oxidize iron (II)-ions or pyrite after 24 h starvation and contact with 1 mM externally added H2O2. In this study, similar results were obtained withAcidiferrobactersp. SPIII/3. However,Acidithiobacillus ferrivoransSS3 showed the highest tolerance towards contact with H2O2, whileLeptospirillum ferrooxidansDSM 2391 was most sensitive. Similar results were obtained after exposure to defined doses of gamma radiation, which cleaves water molecules and generates ROS. In this study members of the three aforementioned genera of mineral-oxidizing bacteria were compared regarding their ability to survive, colonize pyrite and to oxidize iron (II)-ions after exposure to different concentrations of H2O2. Pyrite colonization was studied after exposure to endogenous ROS formed on pyrite or after external addition of H2O2using confocal laser scanning microscopy (CLSM).

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Piperine Exhibits Promising Antibiofilm Activity Against Staphylococcus Aureus by Accumulating Reactive Oxygen Species (ROS)

10.21203/rs.3.rs-514513/v1 ◽

2021 ◽

Author(s):

Sharmistha Das ◽

Payel Paul ◽

Sudipta Chatterjee ◽

Poulomi Chakraborty ◽

Ranojit K. Sarker ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Staphylococcus Aureus ◽

Biofilm Formation ◽

Reactive Oxygen ◽

Antibiofilm Activity ◽

Host Immune System ◽

Oxygen Species ◽

Bacterial Cells ◽

Protein Assay ◽

Area Of Concern

Abstract Biofilm, an aggregated form of microbial existence has been a major area of concern in the healthcare units. These sessile microbes not only protect themselves from the host immune system but also exhibit high resistance against several antimicrobials. One such widely reported Gram-positive pathogen is Staphylococcus aureus. This human commensal is known to cause severe harmful diseases like bacteremia, sepsis, pneumonia, etc. Thus, strategies need to be undertaken to deal with such biofilm challenges. In this respect, we aimed to inhibit microbial biofilm formation of Staphylococcus aureus under the influence of a natural compound, piperine. Our study revealed that the higher concentrations of piperine exhibited considerable antimicrobial activity against Staphylococcus aureus. Hence, lower concentrations of piperine were tested to examine its antibiofilm activity. Several experiments like crystal violet (CV) assay, total biofilm protein assay, and fluorescence microscopy observation established that lower concentrations (8 µg/mL and 16 µg/mL) of piperine showed efficient antibiofilm activity against Staphylococcus aureus. It was also noticed that the lower concentrations of piperine did not compromise the microbial growth of Staphylococcus aureus while exhibiting antibiofilm activity. In this connection, we also noticed that the lower concentrations of piperine showed a considerable reduction in microbial metabolic activity. Furthermore, we observed that the compound was found to accumulate reactive oxygen species in the bacterial cells that could play an important role in the inhibition of biofilm formation. Thus, piperine could be considered as a potential antibiofilm agent against the biofilm formation caused by Staphylococcus aureus.

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Atmospheric organic complexation enhanced sulfate formation and iron dissolution on nano α-Fe2O3

Environmental Science Nano ◽

10.1039/d0en01220c ◽

2021 ◽

Author(s):

Kejian Li ◽

Xiaozhong Fang ◽

Tao Wang ◽

Kedong Gong ◽

Muhammad Ali Tahir ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Reactive Oxygen ◽

Light Irradiation ◽

Oxygen Species ◽

Iron Dissolution ◽

Organic Complexation ◽

Sulfate Formation

The iron–dicarboxylate complexation significantly increased the SO2 heterogeneous conversion on nano α-Fe2O3 and ATD under light irradiation, owing to the generation of strong reactive oxygen species.

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Targeting biofilm inhibition using Quercetin – Interaction with bacterial cell membrane and ROS mediated biofilm control

Functional Foods in Health and Disease ◽

10.31989/ffhd.v8i6.510 ◽

2018 ◽

Vol 8 (6) ◽

pp. 292 ◽

Cited By ~ 1

Author(s):

Sreelatha Sarangapani ◽

Ayyavoo Jayachitra

Keyword(s):

Reactive Oxygen Species ◽

Lipid Peroxidation ◽

Antimicrobial Activity ◽

Biofilm Formation ◽

Biological Activities ◽

Reactive Oxygen ◽

Oxygen Species ◽

Biofilm Inhibition ◽

Biofilm Control ◽

Enhanced Production

Background: Quercetin is an active nutraceutical ingredient widely distributed in foods, vegetables, fruits, and more. Quercetin is a versatile functional food with extensive protective effects against many infectious and degenerative diseases due to their antioxidant activities. Apsergillus niger is a filamentous fungus and the most abundant mold found in the environment. This fungus has been the source of several bioactive compounds and industrial enzymes through biotransformation.Aim: In this report we emphasized the potential of Aspergillus species for the selective conversion of rutin to quercetin, which involved stereoselective and regiospecific reactions with enhanced production and minimization of the formation of toxic wastes. This fungal microbe was able to transform the complex structure of rutin to quercetin with remarkable catalytic activity for the reaction with high product yield. The quercetin produced demonstrated the ability to inhibit biofilm formation and eradicate established biofilm involving the production of reactive oxygen species (ROS) indicative of membrane activity. These results suggest quercetin may have implications in biofilm control targeting reactive oxygen species as a novel therapeutic strategy.Methods: Quercetin was synthesized by microbial biotransformation recruiting Aspergillus niger. The synthesis of quercetin was compared with the chemical process. Furthermore, the quercetin produced by the biotransformation process was characterized by high performance thin layer liquid chromatography. The quercetin produced was assessed for biological activities. The antimicrobial activity, hemolytic activity, inhibition of biofilm by crystal violet staining, and cell viability by confocal laser scanning microscope was assessed. The membrane interaction effect and oxidant scavenging effect by DPPH, Intracellular ROS release, and lipid peroxidation was measured.Results: Quercetin produced by microbial transformation demonstrated antimicrobial activity against S. aureus by effectively inhibiting the growth and dispersion of preformed biofilms. Quercetin demonstrated a significant free radical scavenging activity and significant inhibition of lipid peroxidation. Significant release of reactive oxygen species was observed in bacterial cells.Conclusion: In conclusion, the bio transformed quercetin exhibited disruptive potential of biofilm formation by preventing cell surface attachment and biofilm growth. Therefore, it can be suggested that the major public health benefits could be achieved by substantially increasing the consumption of quercetin rich foods.

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